1. Field of the Invention
The present invention relates to a water jet propulsion boat.
2. Description of the Related Art
A water jet propulsion boat is affected by a backward gravitational acceleration when accelerated, by a forward gravitational acceleration when decelerated, and by a gravitational acceleration opposite to a direction of a turn to the left or right. As a result, oil in an oil pan tends to tilt in various directions. The oil pan, which is arranged on the bottom of the engine compartment, is also shallow and thin because the drive shaft in a water jet propulsion boat must be arranged low in the watercraft body. Therefore, only a limited volume of oil can be stored in the pan, and when the oil tilts, the oil suction port of the oil pump is exposed from the surface of the oil and the oil pump tends to suck in air.
Therefore, in the lubricating apparatus disclosed by Japanese Laid-open Patent Application No. 2008-002455, the oil chamber is divided into a main oil chamber and an auxiliary oil chamber, and a feed pump supplies oil from the main oil chamber to lubricated sections of the engine. A scavenging pump returns the oil in the auxiliary oil chamber to the main oil chamber. As a result, tilting of oil in the main oil chamber is lessened.